This invention relates to a planetary transmission wheel drive mechanism, particularly for applying driving torque to the driving wheels of heavy duty ground engaging vehicles such as trucks, tractors and the like.
Planetary transmission wheel drive mechanisms or axle drives with built in planetary transmissions are already known for the advantage of an increased torque appearing at the end of the force flux so that axle drives of such type are particularly suitable for being comprised in the wheel hubs of trucks, busses and the like since they permit to employ relatively light constructions.
Such axle drives are of substantial importance in case of tractors and similar heavy duty vehicles which require exceedingly high transmissions or step-up gearings in their wheel hubs. As is known, to meet such requirements multistage planetary transmission gears are employed such as described in British patent specification No. 1,222,729 or U.S. Pat. No. 2,529,330. However, the known axle drives of the aforesaid type are relatively expensive because they have been built for special purposes and had to be specially developed for each vehicle type.